It also offers live and pre-match wagering on a range of international sports, as well as a variety of online casino games.

Despite its Australian link, the site is registered by a Panamanian and a trace of its IP address revealed it was based in the Costa Rican capital of San Jose — the hub of the international bitcoin-gambling industry.

The operation does not appear to be licensed by the gambling commission of any of Australian state or territory.

Legal experts have said the site is in clear breach of the federal Interactive Gambling Act, which prohibits websites from offering those forms of online gambling to Australian punters.

However, the CIDA said it could not de-register the site without a request being made by authorities or a member of the public lodging a complaint.

Mr Wilkie, a strong advocate of gambling reform, said that was not good enough.

"The site should be shut down immediately, and the Christmas Island Domain Administration should act straight away to remedy the situation," he said earlier this week.

Following Mr Wilkie's call and reporting of JustBet's activities on the Sports Integrity Initiative website, the Australian Communications and Media Authority (ACMA) announced it had begun investigating the site for breaches of the Interactive Gambling Act.

A spokesperson for ACMA said the act prohibits many forms of online gambling from being offered in Australia, as well as "unlicensed regulated interactive gambling services, such as online wagering services provided without a licence issued by an Australian State or Territory".

"The ACMA has published a register of interactive wagering service providers that are licensed by an Australian state or territory," the spokesperson said.

"Interactive wagering services that are not included on this register are likely to be provided to Australian customers illegally."

The Northern Territory last month took steps to ban gambling operators licensed there from offering bitcoin betting.

While JustBet offers top-tier Australian games on the bitcoin-gambling market, another site takes things further, offering odds on low-level Victorian and Tasmanian soccer fixtures.

Cloudbet, which claims to be registered by the gambling authority of Montenegro, is described as "one of the most impressive options for bitcoin sports bettors".

It has offered a range of local soccer matches for betting, including NPL Tasmania matches involving teams such as the Devonport Strikers, Hobart Zebras and Kingborough Lions, and fourth-tier Victorian matches.